Update dependency com.diffplug.spotless:spotless-maven-plugin to v2.40.0

Author: renovate[bot]

formatter-test/pom.xml

@@ -25,7 +25,7 @@
 <plugin>
 <groupId>com.diffplug.spotless</groupId>
 <artifactId>spotless-maven-plugin</artifactId>
-<version>2.28.0</version>
+<version>2.40.0</version>
 <dependencies>
 <dependency>
 <groupId>de.muenchen.oss</groupId>